The present invention relates to devices for use with wheelchairs having at least one ground engaging wheel of relatively small diameter to enable the wheelchair to mount raised obstacles in its path, for example kerbs, steps and the like. For convenience such devices will hereinafter be referred to as kerb climbing devices, it being understood that the term "kerb" embraces all kinds of raised obstacle which may be encountered in use of a wheelchair.
A kerb climbing device for a wheelchair having a pair of castor wheels at the front and a pair of larger diameter wheels at the rear is known from U.S. Pat. No. 4,132,423 and UK Patent Application No. 2,145,983-A, comprising a strut pivotally mounted on the wheelchair and carrying an arcuate ground engaging shoe at the free outer end. The strut is biassed by a spring to an operative position projecting forwardly of the castor wheels with the shoe raised clear of the ground for engagement with the upper front edge of a kerb to be mounted whereupon the strut is pivotal under the forward momentum of the wheelchair to lift the castor wheels off the ground onto the kerb.
With this type of kerb climbing device, the shoe must have a considerable arcuate extent in order to cooperate with any one of a range of different kerb heights and this can give rise to problems both in fitting the device where the space available is restricted and in use where the upward pojection of the shoe presents a safety hazard.
A further problem is that the point of contact between the shoe and the kerb lies on the longitudinal axis of the strut for one kerb height only and for all other kerb heights is offset so that the loads acting on the strut during lifting of the wheels generate forces tending to bend the strut.
It is an object of the present invention to provide a kerb climbing device which mitigates the aforementioned problems of the known device.